Seal for floating roof tanks



March 2,A 1948.

E. E. SHANOR SEAL FOR FLOATING ROOF TANKS Filed March 23, 1944 2Sheets-Sheet 1 'Il' lll,"

March 2, 1948. E. E. sHANoR 2,436,942

SEAL FOR FLOATING ROOF TANKS Filed larch 23, 1944 2 Sheets-Sheet 2 wwwPatented Mar. 2, 1948 Edgar E. Shanor, Sharon, Pa., acsignor to GeneralAmerican Transportation Corporation, Chicago. IIL, a corporation oi NewYork Application March 23, 1944, Serial No. 527,889

This invention relates to improvements in storage tanks for oil.gasoline and other volatile liquids of the type in which the top or deckis not connected with the wall of the tank, but normally floats upon andis supported vby the liquid in the tank.

In this type of tank there is an annular space between the tank wall andthe deck, in which the level of liquid rises above the bottom of thedeck due to the displacement ofliquid by the deck.

z (ci. zzo-zc) Unless this space is properly closed, undue evaporationof the liquid and consequent loss and possible explosion results. Theclosure means, however, must yield to the drifting of the roof and mustmake sliding contact with the inner surface of the tank wall to allowfor the rise and fall of the deck when the tank is being filled oremptied.

The object of the invention is to provide asealing or closure structurewhich meets the above requirements and at the same time remains gastightunder all operating conditions. I

A furtherfobject 'is to provide for the adjustability of theclosurestructure with respect to the level of the liquid in the annularspace be tween the tank wall and the deck to minimize evaporationadjacent the sliding contact during summer temperatures and preventfreezing ofmoisture adjacent the sliding contact during wintertemperatures.

Other objects of the invention will appear from the followingdescription in connection with the of the closure structure illustratingseveral relative positions thereof resulting from the drifting of thedeck out of concentricity with respect to the tank, and illustratingfurther the closure structure adjusted for summer operation; n

Fig. 3 is an inner face view of several adjacent suspension plateslooking in the direction of the arrows on the line 3,-3 of Fig. 1; and

its upper margin. The floating deck B is circu.. lar in shape and, if ofthe pan type shown in the drawings. comprises a flat bottom wall 2 and avertical'cylindrical wall 3 upstanding therefrom, this vertical wallgenerally being parallel with the wall of the tank. This invention isequally as well adapted to the types. of floating decks which areprovided with air chambers or pontoons. The deck is of less diameterthan the tank, so that there is anannular space C between c the tankwall and that of the deck. The deck is shown inthe drawings as close tothe top of the tank, so that substantially the full capacity of the tankis utilized; but it is understood, of

course, that. the deck which floats on the body of E liquid in the tankrises and falls accordingly as the liquid level is raised or lowered inthe tank. 'I'he deck.l due to its weight, displaces the liquid whichrises in the annular space C to a normal level above the bottom of thetank and indicated by the line B.

'Ihe annular space C is closed or sealed by a flexible curtain or apronD ofsuitable material, such as asbestos fabric or synthetic rubber.which is gastight and iireresistant. This sealing or closure curtainextends continuously around the deck and bridges the gap between thedeck and the tank wall. The upper inner edge of the curtain is clampedagainst the outer face of the deck wall 3 by means' of the straps l anda series of bolts 1, so as to make the joint gastight and securely holdthe curtain in place. The outer and lower margin of the sealing curtainis attached to and supported by a series of suspension members E inclose relation to the innereface of the tank wall. 'I'hese suspensionmembers arein the form of rectangular plates which, for the most partof` their area, are substantially flat, but which'have their lowerportions 8 curved on a suitable radius so that.their outer face makessubstantially a line contact 9 with the inner face of the tank wall,this line contact shifting slightly along the curve of the plates as theplates swing about their fulcrums when the deck drifts into eccentricrelation to the tank wall. These plates are also preferably slightlycurved transversely in the vicinity of the contact with the tank wall,so that they conform to the curvature of the tank wall and thus maintainas close contact throughout their width as possible.

The lower portion ofthe sealing curtain is curved to conform to theinner face of the curved `portions 8 of the suspension members and areclamped against said faces by the curved clamping plates lll which aresecured to the portions Aeach suspension member is closure curtain inclose Contact with the susv @mten as necessary provided. but it beeniound that' one clamping plate disposed in the center oi .1; cient tohold the pension members throughout their width.

The suspension members entend diagonally uns ward beyond the uppermargin it? ci the wall of the deck and are supported on nilcrum helm ormembers iii which permits them to swing radially. They are spaced apartsuciently to allow freedom ci? radial movement without inter-n ferencewith each other; in fact, the spacing such that fairly large openingsare provided be tween the plates which render the suspension membersthemselves ineffective as a sealing or closure means for the annularspace between the deck and the tank wail. Each suspension member isprovided with a plate E' riveted on its inner,

face and extending downward to overlie the up@ per margin of the deckwall and serve as a watershed to minimize the possibility oi. wateraccumulation in the space between the member E and the sealing curtainD.

The iulcrum bolts are i.shaped and have their upper portions It turnedradially outwardly be yond the wall S oi' the' deck where they extendthrough holes I in the suspension members and holes lia in thewatersheds E'. Their outer end portions I8 are reduced to provideshoulders it against which the suspension members bear as fulcrums, theholes Il being sumciently large to provide for the free movement oi" themembers. The members are retained on these fulcrum bolts againstdisplacement by the pins I8. There are preferably two of these fulcrumsupports for each suspension member to prevent them from any rockingmovement in their own. planes. The bolts are positioned adjacent themargins of the suspension members and are mounted on a continuous angleI! which extends around the deck wall 3 and is secured by welding orotherwise to the inner face of the deck wall adjacent the upper marginthereof.

The verticalportions of the fulcrum bolts extend through holes in thehorizontal ange o1' the crevice di to present the sims ci mais turewhich may accumulate 'in the crevice and ireese the suspension membersto the tank wall.

The upper portions ci the suspension members it entend in their sameplane above lthe fulcrum bolts and are acted upon by spi-ins deviceswhich ursethe members yieldinsly outwardly to maintain constant contactwith. the tank wall the angle I9 and are threaded for the locking nuts2l, one of which is positioned on each sidel of the ilange and screwedup tightly thereagainst to firmly hold the fulcrum bolt in position,This construction provides a considerable adiustment by which thesuspension members E may be bodily raised or lowered to-adiustlthecontact lines l of the suspension members with respect to the liquidlevel 5 in the annular space between the deck and the tank wall.

The lower portions l of the suspension members and the clamped lowerportions of the elosure curtain are always submerged in the liquid, butthe position of the contact l with respect to the liquid level isimportant. During summer or warm weather temperatures, it is desirableto adjust the suspension members so that the contact line 8 of thesuspension members coincide substantially with the liquid level I in theannular space, as indicated in Fig. 2. This leaves a minimum of' liquidin the crevice 22 between the tank wall and the suspension memberexposed to evaporation or ilre. On the other hand, during the winter orfreezing temperatures. the suspension members are bodily lowered so thatthe contact 9 is positioned considerably below the liquid level 5, asshown in Fig. 1, whereby a body of non-freezing liquid will bemaintained sion member.` The spring device consists oi the rcel iii, thecoil spring and the supporting bracket liti. The outer end ci the rodentends through a hole in the member it and has a i or cross-head 2dwhich hears against the outer face ci the member E. The spring ismounted on the inner end portion of the rod and is posh tioned betweenthe bracket 2d and a nut il? which is threaded on the rod so that thespring may be placed under the proper degree of compression for thepurpose. e outer end of the spring' bears against a washer member @ilwhich has a bearing face t@ normal to the airis or the spring. Thiswasher member is clamped to the bracket *Zit by means of the bolt il anda nut ti. The boi-t extends through an elongated slot di in the bracket2u, so that the position oi the spring device can be adjusted verticallyin the bracket 2t to conform to thefvertical adjustment of the fulcrumbolts ior the suspension members E. The base oi' the bracket 25 isturned horizontally and is secured to the horizontal :flange oi theangle member l@ by means of the bolt @il and nut 3|.. 'I'he springdevice for each suspension meinber E is preferably positionedsubstantially in the center thereof between the two fulcrum bolts.

I claim:

1. The combination of a storage tank for liquid having a verticalcylindrical wall, a roof deck floated upon the liquidin the tank andhaving a peripheral vertical wall annularly spaced from the tank wall,an annular series of plates disposed in said annular space and havingtheir lower ends curved for contact with the tank wall and their upperends extending above the deck wall, a pair of fulcrum bolts havingoutwardly turned upper ends extending through said plates for pivotallysupporting the plates and having vertically disposed vshank portionsadjustably mounted on the inner side of said deck wall to adjust thecontact of said plates with the tank wall relatively to the liquidlevel, a ilexible continuous curtain secured at its inner edge to thedeck wall and at its outer edge to the said plates below the liquidlevel, and spring devices acting upon said plates above said fulcrumbolts for yieldingly urging the plates in contact with the tank wall. y

2. The combination of a storage tank for liquid having averticalcylindrical wall, a roo! deck floated upon the liquid in thetank and having a peripheral vertical wall annularly spaced from thetank wall. an annular series of plates disposed in said annular spaceand having their lower ends curved for contact with the tank wall andtheir upper ends extending above the deck wall, a pair of i'ulcrum boltshaving outwardlyturned upper v at its inner edge to the deck wall and atits outer m' edge to the said plates below the liquid level, n mans mm5px-mg devices acting' upon said plates bwegidy The following referencesare oi' record in the fulcrum bolts for' yieldingly urging the plates in`ille 0f this patent:

contact with the tank wall, said spring devices 5 UNITED STATES pAmrx-sincluding rod members engaging `the plates above l 2,313,856 WigginsMar, 18. 1943

